Ophthalmologic optical system, ophthalmologic apparatus, and ophthalmologic system

Abstract

To observe the inside of an eye to be examined in a wide range while reducing a burden on an object person with the eye to be examined.SOLUTION: An optical system (28A) includes a reflection mirror unit (280) for forming an image of an eye to be examined (12) by arranging two concave mirrors opposed to each other so as to face each other on an eye to be examined (12) side, which is an upstream side of a first optical unit (281) and a second optical unit (282) that allow a peripheral visual field away from a visual axis to be observed. Since the reflection mirror unit (280) has a conjugated relation between one focal point and the other focal point, the eye to be examined can be observed in a wide range while securing a distance between the eye to be examined (12) and the optical system (28A) by the formation of the image of the eye to be examined (12) by the reflection mirror unit (280).SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The disclosed technology relates to an ophthalmic optical system, an ophthalmic apparatus, and an ophthalmic system. [Background technology]

[0002] Ophthalmic devices for performing ophthalmic diagnosis, ophthalmic surgical procedures, and the like have been realized. In recent years, there has been a demand for an ophthalmic device capable of observing the fundus of a subject's eye (hereinafter referred to as the subject's eye) over a wide range. A wide-angle optical system is used to obtain a wide-field fundus image. When the wide-angle optical system is composed of only a lens, the aperture of the lens becomes large in order to ensure a working distance between the subject's eye and the objective lens. As a result, the wide-angle optical system becomes larger, its weight increases, and its manufacturing costs increase. Furthermore, when a high-resolution image with a wide field of view is obtained using a large-diameter lens, aberration correction becomes complicated. Therefore, there is a demand for an ophthalmic device equipped with a wide-angle optical system capable of obtaining a wide-angle image of the fundus with a simple configuration and high resolution.

[0003] Patent Documents 1 and 2 disclose ophthalmologic apparatuses equipped with optical systems for acquiring wide-angle images of the fundus. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2017-169671 A [Patent Document 2] Special Publication No. 2015-534482 Summary of the Invention

[0005] An ophthalmic optical system according to a first aspect of the disclosed technique is an ophthalmic optical system having a reflection unit including a first concave mirror and a second concave mirror having a parabolic mirror with the same focal length, and a lens unit that receives light from the reflection unit, wherein the first concave mirror and the second concave mirror of the reflection unit each have an aperture on an optical axis, and a focus of the first concave mirror and a focus of the second concave mirror have a conjugate relationship, and at least one of the focus of the first concave mirror and the focus of the second concave mirror is conjugate with the aperture of the other concave mirror. a first concave mirror and a second concave mirror arranged opposite each other so as to be positioned at the opening of the first concave mirror, light rays from the focal point of the first concave mirror are reflected by the first concave mirror and the second concave mirror and focused toward the focal point of the second concave mirror, the lens unit is located at a position conjugate with the pupil of the test eye which is positioned at the opening of the second concave mirror, and is located at the position of the opening of the first concave mirror on the side of the lens unit closest to the test eye, and has an angle conversion lens which converts the light from the reflection unit into light with an angle smaller than the wide angle angle which indicates the angle of the light focused by the reflection unit.

[0006] An ophthalmic apparatus according to a second aspect of the disclosed technology includes a light source that emits light of a predetermined wavelength, the ophthalmic optical system, a scanning member that scans the light from the light source toward the test eye via the lens unit and the reflection unit and is positioned conjugate with the pupil of the lens unit, and an imaging unit that images the fundus of the test eye using the light scanned by the scanning member.

[0007] An ophthalmic system according to a third aspect of the disclosed technology includes a first acquisition unit that acquires a first image of a paraxial region where the fundus of the test eye photographed by the ophthalmic device intersects with the optical axis, a second acquisition unit that acquires a second image of an annular region of the fundus of the test eye surrounding the paraxial region, and a formation unit that combines the first image acquired by the first acquisition unit and the second image acquired by the second acquisition unit to form a wide-area image of the test eye. [Brief description of the drawings]

[0008] [Figure 1] 1 is a block diagram showing an example of an overall configuration of an ophthalmologic apparatus according to a first embodiment. [Diagram 2] 4 is an image showing an example of an illumination angle with respect to a subject's eye of the ophthalmic apparatus according to the first embodiment. [Diagram 3] 2 is a schematic diagram of an optical system in a common optical system included in the ophthalmic apparatus according to the first embodiment. [Figure 4] FIG. 2 is a schematic diagram showing an example of a reflecting mirror unit according to the first embodiment. [Diagram 5] 3 is a schematic diagram showing a state in which an image of a subject's eye is formed by a reflecting mirror unit according to the first embodiment. FIG. [Figure 6] 3 is an image diagram showing an example of an observation image of a subject's eye captured by the optical system according to the first embodiment. FIG. [Figure 7] 1 is a configuration diagram illustrating an example of a configuration of an optical system according to a first embodiment. [Figure 8] 4 is a lateral aberration diagram of the optical system according to the first embodiment. [Figure 9] FIG. 11 is a configuration diagram showing an example of the configuration of an optical system according to a second embodiment. [Figure 10] 11A to 11C are lateral aberration diagrams of the optical system according to the second embodiment. [Figure 11] FIG. 11 is a schematic diagram showing an example of a reflecting mirror unit according to a second embodiment. [Figure 12] 13 is a schematic diagram showing another example of the reflector unit according to the second embodiment. FIG. [Figure 13] FIG. 13 is an image diagram showing an example of a lighting adaptor. [Figure 14] FIG. 13 is a schematic diagram illustrating an example of an optical system according to a third embodiment. [Figure 15] FIG. 13 is a block diagram showing an example of the overall configuration of an image system according to a fourth embodiment. [Figure 16] 13 is a flowchart showing an example of a flow of a process executed by an image display terminal according to the fourth embodiment. [Figure 17] FIG. 13 is an image diagram showing an example of a display screen of a display according to the fourth embodiment. [Figure 18] FIG. 13 is a schematic diagram illustrating an example of an optical system according to a fifth embodiment. [Figure 19]FIG. 13 is a schematic diagram showing an example of a system using attachment and detachment of an optical module according to a fifth embodiment. BEST MODE FOR CARRYING OUT THEINVENTION

[0009] Hereinafter, an embodiment will be described with reference to the drawings.

[0010] [First embodiment] FIG. 1 shows an example of the configuration of an ophthalmologic apparatus 10 according to the present embodiment. The apparatus includes an imaging device 14 that images an eye 12 to be examined, and a control device 16 that controls the imaging device 14. The imaging device 14 includes an SLO unit 18 and an OCT unit 20 as imaging functions. The SLO unit 18 functions as a scanning laser ophthalmoscope (hereinafter referred to as "SLO"). The OCT unit 20 functions as an optical coherence tomography (hereinafter referred to as "OCT"). The control device 16 controls the operation of the imaging device 14 by exchanging information with the imaging device 14. The control device 16 generates an SLO image based on a signal detected by the SLO unit 18. The control device 16 also generates an OCT image based on a signal detected by the OCT unit 20. The control device 16 is realized by, for example, a computer including a CPU (Central Processing Unit), a ROM, and a RAM (Random Access Memory), but is not limited thereto, and may be realized by other hardware configurations. In the following, the posterior segment of the eye, particularly the fundus, will be exemplified as the observation target, but the observation target is not limited thereto and may be the anterior segment of the eye. An example of the anterior segment of the eye is the cornea.

[0011] In the following description, the horizontal direction when the ophthalmic apparatus 10 is placed on a horizontal plane is referred to as the "X direction", and the vertical direction to the horizontal plane is referred to as the "Y direction". The direction toward the bottom is the "Z direction."

[0012] The acquisition of the SLO image is realized by an SLO unit 18 including a light source and a sensor, a scanning device 19 including an optical scanner, and a control device 16 that controls them. Specifically, light emitted from the SLO unit 18 (hereinafter referred to as "SLO light") is irradiated onto the fundus F via the scanning device 19 and the pupil P of the subject's eye 12. The scanning device 19 includes a first scanner 22 (Y direction) and a third scanner 29 (X direction) as optical scanners that scan with the SLO light. Therefore, the SLO light emitted from the SLO unit 18 is two-dimensionally scanned by the scanning device 19. The reflected light reflected by the fundus F is incident on the SLO unit 18 via the pupil P and the scanning device 19. The sensor of the SLO unit 18 generates a signal according to the reflected light and outputs it to the control device 16. The control device 16 generates an SLO image of the fundus F based on the signal detected by the sensor. Since the SLO is a well-known imaging function, a detailed description thereof will be omitted.

[0013] Acquisition of an OCT image, for example, a fundus OCT image, is realized by an OCT unit 20 including a light source, a reference optical system, an interferometer, a spectroscope, and a sensor, a scanning device 19 including an optical scanner, and a control device 16 that controls them. Specifically, light emitted from the light source is branched in the OCT unit 20 and is incident on the reference optical system as reference light and on the scanning device 19 as measurement light. The measurement light is irradiated onto the fundus F via the scanning device 19 and the pupil P. The scanning device 19 includes a second scanner 24 (Y direction) and a third scanner 29 (X direction) as optical scanners that scan the measurement light. Therefore, the measurement light emitted from the OCT unit 20 is two-dimensionally scanned by the scanning device 19. The measurement light reflected by the fundus F is incident on the OCT unit 20 via the pupil P and the scanning device 19. The interferometer of the OCT unit 20 causes interference between the measurement light and the reference light to generate interference light. Each spectral component of the interference light separated by the spectroscope is detected by a sensor. The signal detected by the sensor is input to the control device 16. The control device 16 generates an OCT image of the fundus F based on the detection signal. In this embodiment, an example of the OCT unit 20 is a Spectral Domain OCT (SD-OCT), but is not limited to this. Instead of the SD-OCT, other OCTs, for example, Swept Source OCT (SS-OCT), may be used. Since OCT is a well-known imaging function, a detailed description will be omitted.

[0014] In the following description, when there is no need to distinguish between the SLO light and the OCT measurement light, the SLO light and the OCT measurement light are collectively referred to as scanning light. In addition, it goes without saying that the optical system 28A constituting the common optical system 28 is not limited to functioning as an optical system shared by the SLO and OCT shown in FIG. 1, but can also be used as an optical system for a single purpose, for either the SLO or OCT device.

[0015] Next, the relationship between the scanning angle of the scanning light with respect to the subject's eye 12 and the imaging range on the fundus will be described. As shown in Fig. 2, a scanning angle A of the scanning light SL with the pupil P as the reference position (hereinafter also referred to as external scanning angle A) corresponds to the observer's field of view angle 12A (FOV: Field of View). As the scanning angle A increases, the field of view angle 12A increases. Note that the scanning light SL is refracted by the cornea, and Fig. 2 shows a schematic state in which the scanning light SL is refracted at the center of the pupil P.

[0016] The viewing angle 12A can also be defined by a scan angle B (hereinafter also referred to as an internal scan angle B). The internal scan angle B represents the scan angle of the scanning light SL with the eyeball center O as the reference position. The external scan angle A and the internal scan angle B have different reference positions, but correspond to each other. In the following description, the external scan angle A is used as the scan angle corresponding to the viewing angle 12A. The viewing angle 12A realized by the ophthalmic apparatus 10 having the optical system 28A as a wide-angle optical system is, for example, The external irradiation angle A is about 120 degrees, and the internal irradiation angle B is about 160 degrees. In a conventional ophthalmic device not equipped with a wide-angle optical system, for example, the external irradiation angle A is about 45 degrees, and the internal irradiation angle B is about 60 degrees.

[0017] As described above, the external irradiation angle A corresponds to the viewing angle A, i.e., the range of the fundus that can be imaged. Therefore, in the following description, the viewing angle 12A is referred to as the imaging range 12A. The user can arbitrarily set the imaging position and imaging area within the imaging range 12A by controlling the scanning angle of the scanning device 19.

[0018] Next, the SLO optical system and the OCT optical system will be described. As shown in FIG. 1, the SLO optical system is composed of an SLO unit 18 and a scanning device 19. The OCT optical system is composed of an OCT unit 20 and a scanning device 19. The scanning device 19 includes a first optical scanner 22, a second optical scanner 24, and a third optical scanner 29 as optical scanners for scanning with scanning light. The scanning device 19 further includes a common optical system 28. The third optical scanner 29 is included in the common optical system 28 because it is shared between the SLO optical system and the OCT optical system. The common optical system 28 further includes an optical system 28A as a wide-angle optical system. The scanning light emitted from the third optical scanner 29 is incident on the subject's eye 12 via the optical system 28A. The scanning device 19 further includes a dichroic mirror 26. The dichroic mirror 26 is disposed between the first optical scanner and the third optical scanner. The SLO light emitted from the first optical scanner 22 is guided to the third optical scanner 29 via the dichroic mirror 26. Moreover, the OCT measurement light emitted from the second optical scanner 24 is guided to the third optical scanner 29 via the dichroic mirror 26. The optical path length between the first optical scanner 22 and the dichroic mirror 26 is the same as the optical path length between the second optical scanner 24 and the dichroic mirror 26. The first optical scanner 22, the second optical scanner 24, and the third optical scanner 29 are disposed at positions conjugate with the center of the pupil P. As described above, the dichroic mirror 26 is shared by the SLO optical system and the OCT optical system, and therefore may be included in the common optical system 28.

[0019] Examples of optical scanners include polygon mirrors and galvanometer mirrors. The optical scanners 22, 24, and 29 may be polygon mirrors, galvanometer mirrors, or a combination of these. The optical scanners 22, 24, and 29 are not limited to polygon mirrors or galvanometer mirrors, and may be any deflection optical element that deflects the scanning light in a predetermined direction.

[0020] That is, the ophthalmologic apparatus 10 is required to capture a wide range of images within the imaging range 12A of the fundus of the subject's eye 12. However, when the optical system 28A is configured using only lenses, it is difficult to obtain a wider field of view by making the external irradiation angle A of the subject's eye 12 super wide. This is because it is required to solve several problems, such as ensuring the working distance between the subject's eye 12 and the surface of the optical system closest to the subject's eye 12, improving the aberration performance to obtain a high-resolution image, suppressing flare and ghosting, reducing the size and weight of the device body, and reducing the difficulty and cost of manufacturing. These problems may be contradictory as a wider field of view is sought.

[0021] As described above, there is a demand for an ophthalmic apparatus capable of observing a wide range of the fundus F. In this case, in order to obtain a large imaging range 12A, it is necessary to make the external scanning angle A wider than that of conventional ophthalmic apparatuses. In order to realize a wide external scanning angle A, the ophthalmic apparatus 10 includes an optical system 28A as a wide-angle optical system. The optical system 28A is included in the common optical system 28, and is shared by the SLO optical system and the OCT optical system. Therefore, the ophthalmic apparatus 10 including the optical system 28A can acquire wide-angle SLO images and wide-angle OCT images.

[0022] As shown in FIG. 3, the optical system 28A includes, in order from the subject's eye 12 side, a reflection unit 280 that relays an image of the subject's eye 12, and a first lens group 281 and a second lens group 282 as subsequent lens units. The reflection unit 280 includes a pair of concave mirrors and relays an image of the pupil Pp of the subject's eye 12. The pair of concave mirrors, the first concave mirror 280A and the second concave mirror 280B, are configured so that their focal points are in an aberration-free equal magnification conjugate relationship, as described later. Therefore, a conjugate image of the pupil Pp of the subject's eye 12 arranged near the opening 280Bh of the second concave mirror 280B on the subject's eye side is formed near the opening 280Ah of the first concave mirror 208A on the opposite side to the subject's eye. The image Pp' of the pupil Pp formed near the aperture 280Ah of the first concave mirror 280A is a relay of the pupil Pp near the aperture 280Bh by the reflection unit 280. Therefore, it is preferable that the position of the pupil Pp of the subject's eye and the conjugate position of the pupil formed by the reflection unit 280 match the focal positions of the reflection surfaces 280A and 280B of the reflection unit 280. The pupil Pp of the subject's eye is disposed near the focal position of the first reflection mirror 280A, and the position of the entrance pupil of the composite system of the first lens group 281 and the second lens group 282, i.e., the lens unit, is disposed near the focal position of the second reflection mirror 280B, i.e., at the position of the central aperture 280Ah of the first reflection surface 280A. The image Pp' of the pupil Pp relayed to the aperture 280Ah forms a pupil conjugate image Pcj at a position conjugate with the position of the pupil Pp of the test eye in the space on the opposite side to the test eye 12 by a lens unit having a first lens group 281 including a lens with positive refractive power and a second lens group 282 including a lens with positive refractive power. In addition, in the example of Fig. 3, a distance Xw between the test eye 12 and a reflecting surface 280Ar of a first concave mirror 280A, which is the first optical element of the light beam propagating to the test eye 12, is shown as an example of the working distance between the test eye 12 and a surface of the optical system closest to the test eye 12.

[0023] In addition, the pair of concave mirrors, the first concave mirror 280A and the second concave mirror 280B, each have a concave reflecting surface as described later, but for example, a reflecting mirror having a concave parabolic reflecting surface can be used. In this specification, they may be simply referred to as reflecting mirrors or reflecting surfaces. Furthermore, the reflecting surfaces of first concave mirror 280A and second concave mirror 280B are not limited to parabolic reflecting surfaces, and may be aspheric surfaces formed rotationally symmetrically about the optical axis.

[0024] The first lens group 281 in the lens unit includes a lens for receiving the wide-angle light beam from the reflecting unit 280. This lens is a lens (hereinafter referred to as an angle conversion lens) that converts the angle of the wide-angle light beam from the subject's eye 12 into an angle smaller than the angle of the wide-angle light beam. An image Pp' of the pupil Pp of the subject's eye formed near the opening 280Ah of the first reflecting mirror 280A is an aerial image Since the lens is small, the lens can be arranged in contact with this image. Furthermore, a lens may be arranged in the spatial image of the pupil Pp. Therefore, the aperture of the angle conversion lens for receiving the wide-angle light beam in the first lens group 281 can be made small. As a result, the lens arranged on the subject's eye side of the first lens group 281 can be a small-diameter angle conversion lens. Since the angle of the wide-angle light beam handled by the reflection unit 280 is converted to a small value by this lens, the aperture of the entire first lens group 281 can also be made small. Since the lens aperture of the first lens group 281 is made small, the aperture of the second lens group 282 can also be made small. Therefore, the optical system 28 including the reflection unit 280 can correct various aberrations well while the lens configuration of the lens unit is simple, and an ultra-wide-angle image of the fundus can be acquired with excellent image quality.

[0025] The scanning light SL irradiated from the reflection unit 280 to the fundus F through the pupil P is reflected by the fundus F and enters the reflection unit 280 as reflected light, as shown in Fig. 3. The reflected light enters a lens unit consisting of a first lens group 281 and a second lens group 282 through the reflection unit 280. The reflected light is further entered into the SLO unit 18 via the third optical scanner 29 and the first optical scanner 22, as shown in Fig. 1. The control device 16 generates a wide-angle image of the fundus F based on the signal detected by the sensor.

[0026] In the optical system 28A, the position of the fundus conjugate image Fcj in a conjugate relationship with the fundus F is formed approximately in or near the first lens group 281. The first lens group 281 and the second lens group 282 arranged between the pupil Pp of the subject eye and the position of the pupil conjugate position image Pcj in a conjugate relationship with the pupil Pp of the subject eye are effective in including at least one surface having a negative refractive power in the lens group for aberration correction. The coma aberration of the pupil between the pupil Pp and the pupil conjugate image Pcj becomes a difference in the light beam angle of the fundus image at the image position of the pupil conjugate Pcj, which leads to a change in resolution at the position of the fundus. In order to correct this coma aberration of the pupil, a lens group having a positive refractive power as a whole is arranged between the fundus conjugate Fcj position with the fundus of the subject eye 12 and the pupil conjugate Pcj position, and it is preferable that at least one surface having a negative refractive power is configured in the lens group. In addition, when the ophthalmic device requires fine focus adjustment to the subject's eye, it is preferable to move some of the optical elements along the optical axis. In this embodiment, the second lens group 282, which is the lens group on the opposite side of the subject's eye in the lens unit, can be moved along the optical axis.

[0027] Next, the reflection unit 280 will be described in detail. As shown in FIG. 3, the reflection unit 280 includes a pair of concave mirrors 280A and 280B. The concave mirrors 280A and 280B are formed as parabolic mirrors, and the focal lengths of the two mirrors are equal, and the axial distance between the two mirrors is equal to the focal lengths. The concave mirrors 280A and 280B include central openings 280Ah and 280Bh, respectively, that include the intersection with the optical axis of the reflection unit, and form a donut-shaped annular reflection section. The two concave mirrors 280A and 280B are disposed facing each other. With this arrangement, light incident from the central opening 280Ah on one reflection surface 280A side is reflected by the other reflection surface 280B, and then reflected by one reflection surface 280A toward the central opening 280Bh of the other reflection surface 280B. In particular, by making the concave mirrors 280A and 280B parabolic, the light emitted from the focal point is reflected as a light parallel to the optical axis, and the light parallel to the optical axis is condensed at the focal point. Therefore, when two concave mirrors with parabolic reflecting surfaces are arranged facing each other at a distance of the focal length, an image of an object located at the central opening of one reflecting surface can be formed on the central opening of the other reflecting surface. That is, when the pupil Pp of the subject's eye 12 is positioned at the opening 280Bh, the image Pp' of the pupil Pp is relayed to the position of the opening 280Ah. In this state, when the vicinity of the opening 280Ah is observed from the first reflecting surface 280A side, it is observed as if the pupil P is raised. The image of the pupil Pp relayed by the reflecting unit 280 is treated in the same way as the pupil Pp.

[0028] 3, the opening 280Ah of the first concave mirror 280A and the opening 280Bh of the second concave mirror 280B can be formed as a physical opening space (hole) formed at the center of the reflecting surface, but in order to prevent dirt and dust from entering the space between the pair of concave mirrors, they can be formed as a transmitting surface formed in the center of the concave mirror. In particular, the opening 280Ah of the first reflecting mirror 280A arranged on the opposite side of the subject's eye can be configured to receive the most advanced lens (angle conversion lens) of the lens unit as described above, or can be formed as a transmitting surface to which the angle conversion lens is bonded. The opening formed in the concave mirror is not limited in shape as long as it can pass light. Generally, the shape of the opening is circular, but it may be elliptical, polygonal, or asymmetric. The smaller the size of the opening, the better, since the reflection unit will block the area on the optical axis. However, if the central opening of the concave mirror 280B on the side of the subject's eye is small, the face of the subject's eye will come into contact with the concave mirror, so the opening must be large enough to avoid contact. The central opening of the concave mirror 280A on the opposite side to the subject's eye is essential to guide the light emitted from the reflection unit 280 to the subsequent lens unit, and is determined in balance with the size of the central blockage.

[0029] Of the pair of concave mirrors constituting the reflection unit 280, the concave mirror 280A is as shown in FIG. As shown, the first reflecting surface 280A has a paraboloid with a focal length f. The concave mirror 280B has a paraboloid with a focal length f. The two concave mirrors 280A and 280B are arranged so that the focal point of the first reflecting surface 280A overlaps with the apex of the second reflecting surface 280B. In this manner, the focal points of the concave mirrors coincide with each other, and the concave mirrors are arranged opposite each other with a distance of the focal length between them, so that the focal points are in an equal magnification conjugate relationship without aberration. The example shown in FIG. 4 shows a case where the focal point 280Af of the first reflecting surface 280A overlaps with the apex of the second reflecting surface 280B (for example, the center of the second reflecting surface 280B), and the focal point 208Bf of the second reflecting surface 280B overlaps with the apex of the first reflecting surface 280A (for example, the center of the first reflecting surface 280A).

[0030] When the reflecting surfaces are extended until the first reflecting surface 280A and the second reflecting surface 280B intersect with each other, the maximum half angle C at which the first reflecting surface 280A and the second reflecting surface 280B can reflect each other is uniquely determined and is about 70.5 degrees. If the straight line passing through the intersection of the first reflecting surface 280A and the second reflecting surface 280B is the x-axis and the straight line passing through the vertex of the first reflecting surface 280A and the vertex of the second reflecting surface 280B is the y-axis, the first reflecting surface 280A is expressed by the following formula (1). The second reflecting surface 280B is expressed by the following formula (2). In this way, when two concave mirrors 280A and 280B having parabolic surfaces are arranged opposite each other, an image of the object is formed on the other reflecting surface by placing an object on one of the reflecting surfaces. In this embodiment, the subject's eye 12 is observed using the reflecting unit 280. y=-x 2 / 4f+f / 2 (1) y=+x 2 / 4f+f / 2 (2)

[0031] 5 is a schematic diagram showing a state in which an image of the subject's eye 12 is formed by the reflecting unit 280 according to the present embodiment. In the reflecting unit 280, a first reflecting surface 280A and a second reflecting surface 280B are provided with central openings 280Ah and 280Bh, respectively, and the opening 280Ah of the second reflecting surface 280B is provided with central openings 280Bh. When the subject's eye 12 is positioned at 0Bh, an image 12Z of the subject's eye 12 is formed near the opening 280Ah of the first reflecting surface 280A. When the vicinity of the opening 280Ah of the first reflecting surface 280A is observed from the outside of the reflecting unit 280 (the right side in the figure) in the state shown in Fig. 5, the subject's eye 12 is observed as if it were floating out. It is possible to treat the image 12Z of the subject's eye 12 formed by the reflecting unit 280 in the same way as the subject's eye 12. That is, since the spatial image of the subject's eye is formed on the opening 280Ah by the reflecting unit 280, a sufficient optical distance Xw is ensured.

[0032] Next, FIG. 6 shows an example of a wide-angle image (hereinafter, also referred to as a wide-angle SLO image) of the fundus F captured by the optical system 28A. The reflected light reflected by the fundus F is incident on the first lens group 281 and the second lens group 282 via the reflecting unit 280 as shown in FIG. 3. The reflected light is further incident on the SLO unit 18 via the first optical scanner 22 as shown in FIG. 1, and a wide-angle image of the fundus F generated by the control device 16 is shown. Of the reflected light that passes through the opening 280Ah of the reflecting unit 280, a part of the reflected light, i.e., paraxial light in a direction substantially along the optical axis AX, is emitted to the first lens group 281 without being reflected by the reflecting unit 280. Therefore, as shown in FIG. 6, a fundus image is not depicted in the center of the wide-angle image, i.e., in the central region corresponding to the openings 280Ah,Bh. In the region corresponding to the openings 280Ah,Bh, for example, a blurred image of the anterior eye is formed. The light from the subject's eye passing through these central openings is incident on the lens unit without passing through the reflecting unit 280, and the lens unit can form an image of the anterior segment of the eye. Although the position of this image does not coincide with the position of the fundus image, since the image is formed by paraxial rays, the focal depth is quite deep, and it is possible to obtain an image of the anterior segment of the eye, even if it is slightly blurred, and this can be used for alignment of the subject's eye.

[0033] The size of the central region where the fundus image is not depicted corresponds to the diameter of the openings 280Ah and 280Bh. From the viewpoint of reducing the central region where the fundus image is not depicted, it is preferable that the effective diameter of the openings 208Ah and 208Bh provided on each reflecting surface of the reflecting unit 280 is as small as possible. For example, by determining the effective diameter of the opening 208 to a diameter that matches the size of the pupil of the subject's eye 12 or a diameter that includes the diameter, it is possible to limit the area of ​​the retinal image of the central part of the subject's eye 12, which is difficult to obtain, to the smallest possible area.

[0034] Example 1 Next, an optical system 28A according to Example 1 will be described with reference to Fig. 7. The same components as those in the first embodiment are denoted by the same reference numerals, and detailed description thereof will be omitted.

[0035] The light beams shown in FIG. 7 show how the optical system 28A forms a pupil conjugate point Pcj in a space on the opposite side to the eye 12. The optical system 28A includes, in order from the eye 12 side, a reflecting unit 280, a first lens group 281, and a second lens group 282. The reflecting unit 280 includes, in order from the pupil Pp side of the eye 12, a mirror module M01 in which a second reflecting surface 280Br and a first reflecting surface 280Ar are arranged. The first lens group 281 includes, in order from the pupil Pp side, a positive meniscus lens L01 with a concave surface facing the pupil Pp side as an angle conversion lens, a negative meniscus lens L02 with a convex surface facing the pupil Pp side, a biconvex positive lens L03, and a positive meniscus lens L04 with a concave surface facing the pupil Pp side. The positive lens L01 is disposed so that its surface on the pupil Pp side is in contact with the image of the pupil Pp formed near the opening 280Ah of the reflecting surface 280A. The negative meniscus lens L02 and the biconvex positive lens L03 are cemented together to form a cemented positive lens component, and the surface on the opposite side to the pupil Pp has an aspheric surface. The second lens group 282 has, in order from the pupil Pp side, a positive lens L05, a biconvex positive lens L06, and a biconcave negative lens L07. The biconvex positive lens L06 and the negative lens L07 are cemented together to form a meniscus lens component with a convex surface facing the pupil Pp side. All of these optical elements are disposed along a single optical axis AX.

[0036] Here, the positive lens L01 arranged closest to the pupil Pp side of the first lens group 281 functions as an angle conversion lens. That is, the lens surface on the pupil Pp side is arranged near the light collecting position by the reflection unit 280, that is, slightly away from the vicinity of the focus of the second parabolic mirror 280B, and the surface on the pupil Pp side is a flat surface or a weak concave surface, and has a strong positive refractive power on the side opposite to the pupil Pp, thereby converting the extremely wide-angle light reflected by the two parabolic surfaces of the reflection unit 280 into light with a small exit angle. Therefore, it is clear that the aperture of the first lens group 281 and the second lens group 282 is configured to be extremely small compared to the aperture of the reflection unit 280 due to the positive lens L01 as the angle conversion lens. Note that, when the surface on the pupil Pp side of the positive lens L01 as the angle conversion lens is made concave, the central part of the first concave mirror 280A can be configured as an opening as a transmission surface, and the positive lens L01 can be cemented to this transmission surface.

[0037] The parallel light beam emitted from the first lens group 281 becomes slightly divergent light and enters the subsequent second lens group 282. The second lens group 282 converts the weak divergent light from the first lens group 281 into a parallel light beam, and forms a conjugate image Pcj of the pupil Pp of the test eye 12 in a space on the opposite side of the test eye 12 by the configuration with the first lens group 281. That is, a light beam equivalent to the parallel light beam emitted from the position of the pupil P of the test eye 12 is emitted by the reflection unit 280, and a pupil conjugate point Pcj is formed via the first lens group 281 and the second lens group 282. Here, it is assumed that the light from the fundus is emitted as a parallel light beam from the test eye 12. In this case, the conjugate point with the fundus of the test eye 12 is the position indicated by point Fcj in FIG. 7, and a primary spatial image Fcj of the fundus is formed between the optical elements (lenses L03 and L04) of the first lens group 281. It goes without saying that in the above-mentioned SLO unit 18 and OCT unit 20, the scanning light SL (laser light) from each unit is incident on the subject's eye 12 at various angles as a parallel light beam centered on the position of the pupil P. In this way, as described in Fig. 3, this optical system 28A has a function of forming an image of the pupil Pp of the subject's eye on its conjugate image Pcj, and has a function as a pupil relay system. The same applies to the embodiments described later.

[0038] The imaging performance can be improved by appropriately making each lens surface of the above-mentioned lens elements aspheric. These aspheric surfaces are expressed by the following formula (3), where r is the height in the direction perpendicular to the optical axis, z is the distance (sag) along the optical axis from the tangent plane at the apex of the aspheric surface to the position on the aspheric surface at the height r, c is the inverse of the apex curvature radius, k is the conic coefficient, and A, B, C, D, E, F, G, H, and J are the n-th order aspheric coefficients.

[0039] z=(c r 2 ) / 〔1+{1-(1+k)·r 2 ·c 2} 1 / 2 〕 +A·r 4 +B·r 6 +C·r 8 +D·r 10 +E·r 12 +F·r 14 +G·r 16 +H·r 18 +J·r 20 (3)

[0040] Table 1 below shows the values ​​of the specifications of the optical system 28A in the first embodiment. Table 1 shows a case where the effective viewing angle (external illumination angle A from the pupil) is 140 degrees (pupil exit half angle is 70 degrees) and the entrance pupil diameter is 2 mm.

[0041] [Table 1]

[0042] In addition, in the mirror M01, the first reflecting surface and the second reflecting surface of surface numbers 2 and 3 have a conic coefficient k=-1. For surface number 8 of lens L03, the conic coefficient k=0 and the aspheric coefficients are A:+0.415921E-05 B:+0.770893E-07 C:-0.228405E-09 D:+0.182991E-11 E:-0.558798E-14 F:-0.208417E-16 G:+0.119039E-18 H:+0.765206E-22 J:-0.681444E-24 It is.

[0043] 8 shows a lateral aberration diagram of the optical system 28A configured according to the specifications in Table 1. This lateral aberration diagram is an aberration diagram of a fundus image when an aberration-free ideal lens is conveniently placed at the pupil conjugate Pcj position in order to evaluate the optical performance of this embodiment. In each embodiment described later, aberration calculation is performed by similarly placing an aberration-free ideal lens. In the aberration diagram shown in FIG. 8, the vertical axis represents image height, the solid line represents a central wavelength of 587.5618 nm, the dashed line represents 656.2725 nm, the one-dot chain line represents 486.1327 nm, and the two-dot chain line represents 435.8343 nm.

[0044] As is clear from the aberration diagram shown in Fig. 8, in the optical system 28A of the first embodiment, the variation in aberration is suppressed for light in the visible light wavelength range, and it is found that the aberration is corrected well. It is also found that the optical system 28A is corrected well even when the effective viewing angle (i.e., the external illumination angle A) is in the range of 60 degrees to 140 degrees (the pupil exit half angle is 30 degrees to 70 degrees). Although not shown in the figure, it has been confirmed that various aberrations such as spherical aberration, astigmatism, and distortion aberration are also corrected well.

[0045] Example 2 Next, an optical system 28A according to Example 2 will be described with reference to Fig. 9. Example 2 is a modified example of Example 1, and the same components as those in the first embodiment and Example 1 are denoted by the same reference numerals and detailed descriptions thereof will be omitted.

[0046] The light beams shown in FIG. 9 show how the optical system 28A forms a pupil conjugate point Pcj in a space on the opposite side to the eye 12. The optical system 28A includes, from the eye 12 side, a reflecting unit 280, a first lens group 281, and a second lens group 282. The reflecting unit 280 includes, from the pupil P side of the eye 12, a mirror M01 on which a second reflecting surface 280B and a first reflecting surface 280A are arranged. The first lens group 281 includes, from the pupil Pp side, a negative meniscus lens L01 including an aspheric shape with a convex surface facing the pupil P side, a positive meniscus lens L02 with a concave surface facing the pupil Pp side, a negative meniscus lens L03 with a convex surface facing the pupil Pp side, a biconvex positive lens L04 bonded to the lens L03, and a positive meniscus lens L05 with a concave surface facing the pupil Pp side. The negative meniscus lens L03, and the lens L03 and the biconvex positive lens L04 form a cemented positive lens component. The second lens group 282 has, in order from the pupil Pp side, a positive lens L06, a negative meniscus lens L07 with a convex surface facing the pupil Pp side, and a positive meniscus lens L08 with a convex surface facing the pupil Pp side. Here, the negative meniscus lens L07 and the positive meniscus lens L07 form a cemented meniscus lens component. All of these optical elements are arranged along a single optical axis AX.

[0047] The first lens group 281 according to this embodiment has a negative meniscus lens L01 as an angle conversion lens for receiving a wide-angle light beam from the reflecting unit 280 and converting it into a small-angle light beam. The convex surface of the negative meniscus lens L01 is disposed closer to the subject's eye 12 than the conjugate position of the pupil Pp, so that the lens diameter of the negative meniscus lens L01 can be made small. The angle of the wide-angle light beam handled by the reflecting unit 280 is converted to a small angle by this small-diameter angle conversion lens L01, so that the diameter of the subsequent optical elements constituting the first lens group 281 is also made small. Since the diameter of the optical elements constituting the first lens group 281 is made small, the diameter of the optical elements constituting the second lens group 282 is also made small. Therefore, in the optical system 28 including the reflecting unit 280, a wide-angle optical system with a small number of lenses is realized. In addition, since the diameter of the angle conversion lens can be made small, a wide-angle image of the fundus can be acquired with good aberration performance. Furthermore, compared to the optical system 28A according to the first embodiment, aberration correction is made easier, and as a result, a wide-angle image with higher accuracy can be acquired.

[0048] In this embodiment, the angle conversion lens provided at the tip of the lens unit closest to the test eye is a negative meniscus lens L01, because the lens surface is located closer to the test eye than the pupil conjugate position, i.e., the center of rotation of the scanned parallel light beam, i.e., the conjugate position of the pupil Pp. If the angle conversion lens is in contact with the pupil conjugate position or is farther away from the test eye than this position, it is effective to use a positive lens as in the embodiment 1 shown in FIG.

[0049] Table 2 below shows the values ​​of the specifications of the optical system 28A in the second embodiment.

[0050] [Table 2]

[0051] In addition, in the mirror M01, the first reflecting surface and the second reflecting surface of surface numbers 2 and 3 have a conic coefficient k=-1. For surface number 4 of lens L01, the conic coefficient k=0 and the aspheric coefficient are A:+0.746884E-04 B:-0.776642E-06 C:+0.648680E-08 D:-0.395590E-10 E:+0.158555E-12 F:-0.394995E-15 G:+0.574153E-18 H:-0.439516E-21 J:+0.135981E-24 It is.

[0052] FIG. 10 shows a lateral aberration diagram of the optical system 28A configured according to the specifications in Table 2. In the aberration diagram shown in FIG. 10, similarly to the first embodiment, the vertical axis represents image height, the solid line represents a central wavelength of 587.5618 nm, the dashed line represents 656.2725 nm, the one-dot chain line represents 486.1327 nm, and the two-dot chain line represents 435.8343 nm.

[0053] As is clear from the aberration diagram shown in FIG. 10, similarly to the optical system 28A of the first embodiment, it is understood that the variation in aberration for light in the visible light wavelength range is suppressed and is well corrected.

[0054] Second Embodiment Next, a second embodiment will be described with reference to Figures 11 and 12. The second embodiment has the same configuration as the first embodiment, except for a reflection unit 280. The same components as in the first embodiment are denoted by the same reference numerals, and detailed description thereof will be omitted.

[0055] The reflection unit 280 according to the first embodiment includes a first reflecting surface 280A and a second reflecting surface 280B which are paraboloids of revolution with the same focal length f, and is configured such that one focus coincides with the vertex of the other so that their foci have an aberration-free equal magnification conjugate relationship. The reflection unit 280 according to the second embodiment has different focal lengths for the first reflecting surface 280A and the second reflecting surface 280B.

[0056] As described above, the smaller the effective diameter of the aperture provided in the reflection unit 280, the more preferable it is, and the positions of the pupil of the eye to be examined 12 and the pupil formed by the first lens group 281 and the second lens group 282 are preferably adapted to the focal positions of the reflecting surfaces of the reflection unit 280. However, with respect to the setting of the position of the pupil of the eye to be examined 12 and the position of the pupil formed by the first lens group 281 and the second lens group 282, the degree of freedom decreases. Also, the aberration correction in the first lens group 281 and the second lens group 282 is restricted by the angle (emission angle) of the light beam from the reflection unit 280. Therefore, in the present embodiment, an optical system 28A that is easy to handle is provided while maintaining the basic conjugate relationship of the reflection unit 280 in which at least one of the foci of the first concave mirror and the second concave mirror constituting the reflection unit 280 is located at the aperture of the other concave mirror.

[0057] FIG. 11 shows an example of the reflection unit 280 according to the present embodiment. The focal length fa of the first reflecting surface 280Ar is smaller than the focal length fb of the second reflecting surface 280Br (fa < fb). The focus 280Af of the first reflecting surface 280Ar coincides with the vertex of the second reflecting surface 280Br (for example, the center of the second reflecting surface 280Br). On the other hand, the focus 280Bf of the second reflecting surface 280Br is located on the side of the first lens group 281, away from the vertex of the first reflecting surface 280Ar (for example, the center of the first reflecting surface 280Ar). Since the foci 280Af and 280Bf are located on the same optical axis, their conjugate relationship is maintained.

[0058] 11, when the subject's eye 12 is arranged on the second reflecting surface 280Br side and the observation optical system (the first lens group 281 and the second lens group 282) is arranged on the first reflecting surface 280Ar side, the effective viewing angle (external irradiation angle A from the pupil) on the subject's eye 12 side becomes larger than 141 degrees. In this example, the half angle of the external irradiation angle A is indicated by the pupil exit half angle θpp, and the pupil exit half angle θpp becomes larger than 70.5 degrees. On the other hand, the angle θoj on the observation optical system side corresponding to the pupil exit half angle θpp becomes smaller than 70.5 degrees. Therefore, aberration correction in the observation optical system becomes easier than that in the reflection unit 280 in which concave mirrors of the same focal length f are arranged opposite each other.

[0059] However, the space (center occlusion) for passing the light beam toward the observation optical system is larger than that of the reflection unit 280 in which concave mirrors with the same focal length f are arranged opposite each other. In the example shown in Fig. 11, the space (center occlusion) for passing the light beam toward the observation optical system, that is, the angle from the subject's eye 12 side for obtaining the opening 280Ah, is indicated by angle θx.

[0060] In this case, if the line passing through the half-value position of the focal length fa of the first reflecting surface 280A is taken as the x-axis and the line passing through the vertex (e.g., the center) of the second reflecting surface 280Br is taken as the y-axis, the pupil exit half angle θpp is expressed by the following equation (4), and the angle θx is expressed by the following equation (5). θpp=tan -1 ((A / C) 1 / 2 / (A / 4-C)) ···(4) θx=tan -1 ((B(A / C) 1 / 2 / (A / 4-B 2 / C)) ···(5) where A = 4fa, B = fb-fa, and C = (fa·fb) / (fa+fb).

[0061] Therefore, the relationship between the above expressions (4) and (5) can be used to find values ​​that optimize the ease of aberration correction in the observation optical system and the size of the aperture 280Ah. In practice, the angle θx at which the opening 280Ah of the first reflecting mirror 280A is viewed from the subject's eye is as follows: θx≦22.5 degrees It is preferable to form the reflecting surface on the lens unit side so as to have an opening that satisfies the conditional expression shown below. This angle corresponds to the radius of the central occlusion of the annular shape image of the fundus of the subject's eye 12, so the smaller the angle, the more advantageous it is. However, satisfying this condition is advantageous when combining with a central image obtained by a conventional device that can obtain an image centered on the optical axis, as shown in FIG. 6.

[0062] As described above, the focal point 280Bf of the second reflecting surface 280Br is set away from the first reflecting surface 280Ar, so that the reflecting unit and the subsequent lens unit, particularly the angle conversion lens at the tip, can be provided at a distance. Therefore, if impurities such as dust get into the reflecting unit, it becomes easier to remove the impurities, which is effective not only in manufacturing but also in maintenance.

[0063] (Modification) 12 shows a modified example of the reflecting unit 280 according to this embodiment. In this example, the focal length fa of the first reflecting surface 280Ar on the side located farther from the subject's eye 12 is greater than the focal length fb of the second reflecting surface 280Br (fa>fb). With this configuration, the subject's eye 12 is set at a position away from the second reflecting surface 280Br, and as a result, a space can be formed between the subject's eye 12 and the reflecting unit 280. This makes it possible to ensure the distance between the subject's eye and the rear surface (convex surface) of the second parabolic mirror 280B, improving usability.

[0064] As the second embodiment described above, in the configuration shown in FIG. 11 and FIG. 12, the focal length of the first reflecting mirror of the reflecting unit, i.e., the concave mirror farther from the eye to be examined, is denoted as fa, and the focal length of the second reflecting mirror, i.e., the concave mirror closer to the eye to be examined, is denoted as fb. Let us assume that both focal lengths are positive, and 0≦|fa-fb|≦0.1(fa+fb) It is effective to satisfy the above condition from the viewpoints of limiting the size of the central aperture and correcting aberrations.

[0065] In the above configuration, the focal point of each reflecting mirror is basically located at the central aperture of the other reflecting mirror, and as mentioned above, the greater the difference in focal length, the greater the degree of central obstruction. However, it is practical to achieve an optimal balance for the entire device within the above range, including the compactness of the device and the distance between the subject's eye and the device. And, the focal point of one reflecting surface is located at the central aperture of the other reflecting surface. In any case, it goes without saying that, while the basic form is the premise, some deviation is permitted in order to optimize the entire apparatus, including the aberration balance.

[0066] In the first and second embodiments, the optical system 28A including one reflecting unit 280 has been described, but the present invention is not limited to this. It is possible to combine two or more reflecting mirror units and connect them by aligning the pupils of the reflecting units. Also, as described in the second embodiment, the focal lengths of the first reflecting surface 280A and the second reflecting surface 280B may be different.

[0067] By using a plurality of reflecting units 280, it becomes possible to perform processing on the relayed pupil of the subject's eye 12.

[0068] For example, the periphery of the relayed image of the pupil P is directly illuminated by a light source, and illumination of the fundus of the subject's eye 12 is possible. An illumination adapter 280Lt, an example of which is shown in FIG. 13, is provided around the periphery of the relayed image of the pupil P to illuminate the periphery of the relayed image of the pupil P. The illumination adapter 280Lt includes an illumination light source 280Fv arranged to surround the relayed pupil image Pp'. In FIG. 13, a plurality of illumination light sources 280Fv arranged in a ring shape are provided around a circular space having a diameter equivalent to the aperture diameter of the aperture provided in the reflecting surface 280. This ring-shaped illumination light source re-forms an image around the pupil of the subject's eye and illuminates the inside of the subject's eye. Since the imaging light beam passes through the center including the optical axis on the cornea and the illumination light is ring-shaped, the imaging optical path and the illumination optical path to the fundus can be separated, making it possible to prevent the corneal reflection light from being mixed into the imaging light.

[0069] Furthermore, the reflection unit 280 has openings 280Ah, 280Bh at the center of its optical axis. Light passing through these openings 280Ah, 280Bh proceeds directly to the first lens group 281 and the second lens group 282. Thus, by adding a lens to the optical axis of at least one of the first lens group 281 and the second lens group 282 or by changing the distance between the lenses, it is possible to improve the image accuracy near the center of the optical axis.

[0070] Third Embodiment Next, a third embodiment will be described with reference to Fig. 14. The third embodiment has the same optical configuration as the first and second embodiments, and the same components as those in the first embodiment are denoted by the same reference numerals and detailed description thereof will be omitted. In the first and second embodiments, optical system 28A includes reflection unit 280, first lens group 281, and second lens group 282 (see FIG. 7). In the third embodiment, optical elements of optical system 28A are classified according to their functions.

[0071] As shown in FIG. 14, the optical system 28A is divided into a first optical system 28A-1 and a second optical system 28A-2. The second optical system 28A-2 includes lenses L02 to L07, and is configured to function as a fundus imaging optical system with a normal angle of view that enables fundus observation with paraxial rays (that is, narrow field observation). On the other hand, the first optical system 28A-1 includes a reflecting unit 280 and a lens L01. The lens L01 is formed to function as an angle conversion lens. That is, the lens L01 converts the angle of the super-wide-angle light ray from the subject's eye 12 via the reflecting unit 280 into an angle smaller than the angle of the optical light ray. Thus, the first optical system 28A-1 is inserted between the subject's eye and the second optical system 28A-2 to form a part of an optical system that realizes wide-field observation, and the first optical system 28A-1 and the second optical system 28A-2 are arranged on the same optical axis to function as an optical system that realizes wide-field observation.

[0072] Therefore, the optical system 28A is divided into a first optical system 28A-1 and a second optical system 28A-2. By configuring the second optical system 28A-2 separately, and by attaching and detaching the first optical system 28A-1, it is possible to provide an apparatus for both super-wide-angle field observation and narrow-field observation. When the second optical system 28A-2 is formed to function as an optical system that enables fundus observation with paraxial light, the second optical system 28A-2 is configured to be movable in the optical axis direction toward the subject's eye 12, so that when the first optical system 28A-1 is detached, it is possible to easily switch from wide-field observation to narrow-field observation. With this configuration, the same optical system (second optical system 28A-2) can be used for both wide-field and narrow-field observation.

[0073] When providing the optical module 28A-1, it is preferable to configure it as an integrated structure in which the lens L01 for angle conversion is attached to the reflection unit 280. Also, the lens L01 may be attached to the reflection unit 280 via an attachment.

[0074] In the above, the optical unit 28A, which is a combination of the reflection unit 280 and the lens unit, cannot obtain information on the fundus area centered on the optical axis, but it is possible to obtain information on a wide fundus by shifting the position of the subject's eye 12 relative to the optical axis and taking multiple images, and supplementing the information on the central area from the multiple images obtained. That is, by moving the visual axis and the optical axis to different positions multiple times and taking images, it is possible to obtain an image of an area that is difficult to obtain when the visual axis and the optical axis are aligned and taken. It is also possible to combine the multiple images obtained to form one wide-area image. In this case, the visual axis of the subject's eye may be appropriately set by presenting a fixation target (not shown) to the subject's eye and having the subject look at the presented fixation target.

[0075] [Fourth embodiment] Next, a fourth embodiment according to the disclosed technique will be described. The fourth embodiment has the same configuration as the first to third embodiments, and the same components as the first to third embodiments are denoted by the same reference numerals and will not be described in detail. 15 shows an image system 100 as an example of an ophthalmic system capable of providing all images of an imaging range 12A according to the fourth embodiment. The image system 100 includes a first ophthalmic device 110, a second ophthalmic device 120, a network 130 such as the Internet or a local area network, an image server 140, and an image display terminal 150.

[0076] As shown in FIG. 15, the image system 100 includes a first ophthalmic device 110, a second ophthalmic device 120, an image server 140, an image display terminal 150 (e.g., a computer 150, hereinafter also referred to as a PC 150), and a network 130 such as the Internet and a local area network for networking these. The first ophthalmic device 110 is, for example, a normal ophthalmic device (hereinafter also referred to as a narrow-angle ophthalmic device 110) that provides an imaging range of about 45 degrees at an external scanning angle A. A narrow-angle fundus image depicting a fundus region (paraxial region) near the optical axis AX is acquired using the first ophthalmic device 110. The second ophthalmic device 120 is, for example, any of the ophthalmic devices 10 according to the above embodiments, a wide-angle ophthalmic device (hereinafter also referred to as a wide-angle ophthalmic device 120) that provides an imaging range of about 130 degrees at an external scanning angle A. A wide-angle fundus image is acquired using the second ophthalmic device 120. Below, an SLO image of the fundus F will be illustrated as an example, but is not limited to this. As described above, the ophthalmologic image handled by the imaging system 100 may be an OCT image of the fundus F or an image of the anterior segment.

[0077] 6, the wide-angle fundus image acquired by the second ophthalmic device 120 does not depict the fundus image in the center of the image, i.e., in the vicinity of the optical axis AX. Therefore, in this embodiment, a narrow-angle fundus image acquired by the first ophthalmic device 110 and a wide-angle fundus image acquired by the second ophthalmic device 120 are used to generate a wide-angle fundus image in which the fundus image is depicted in its entirety.

[0078] The first ophthalmic device 110 transmits the included angle data associated with the patient ID via the network 130. The second ophthalmic apparatus 120 transmits the wide-angle fundus image data associated with the patient ID to the image server 140 via the network 130. The image server 140 manages these image data. The image server 140 exchanges various information with the PC 150 via the network 130. The image server 140 transmits the fundus image data to the PC 150 in response to an instruction from the PC 150. The PC 150 stores an image processing program for generating a wide-angle fundus image in which the entire fundus image is depicted by combining the narrow-angle fundus image acquired by the first ophthalmic apparatus 110 and the wide-angle fundus image acquired by the second ophthalmic apparatus 120.

[0079] In this embodiment, an image system 100 is described in which the PC 150 is independent of the first ophthalmic apparatus 110 and the second ophthalmic apparatus 120. However, the first ophthalmic apparatus 110 and the second ophthalmic apparatus 120 may have the functions of the PC 150.

[0080] Next, the image processing program will be described. The user instructs the PC 150 to execute the image processing program by using the electronic medical record screen displayed on the display of the PC 150. FIG. 17 shows an electronic medical record screen 200 displayed on the display of the PC 150. The screen 200 includes a display area 201 for displaying patient information, a display area 202 for displaying a narrow-angle fundus image 203G acquired by the first ophthalmic device 110, and a display area 204 for displaying a wide-angle fundus image 205G acquired by the second ophthalmic device 120. The display area 202 includes a display area 202A for displaying the model name of the first ophthalmic device 110. The display area 204 includes a display area 204A for displaying the model name of the second ophthalmic device 120. The screen 200 includes an instruction button 206 for reading an OCT image, an instruction button 207 for instructing execution of an artificial intelligence diagnosis on an ophthalmologic image, and an instruction button 208 for instructing various settings.

[0081] FIG. 16 shows the flow of processing of the image processing program executed by the PC 150. First, in step S100 shown in FIG. 16, a process of acquiring patient information is executed, and the acquired patient information is displayed on the display 156.

[0082] In the next step S102, a fundus image of the patient is acquired, and in the next step S104, it is displayed on the electronic medical record.

[0083] 16, a process of instructing to capture an image of the second fundus image region 12G2, which is the periphery of the central portion of the fundus, is executed, and a negative determination is made in step S108 until the image capturing is completed. If a positive determination is made in step S108, a captured image of the fundus around the central portion of the subject's eye 12 of the patient ID is acquired in step S110. The second ophthalmic device 120 captures an image of the fundus around the central portion of the subject's eye 12 of the patient ID upon receiving an instruction from the image display terminal 150, and outputs the captured image to the image display terminal 150. The fundus capturing around the central portion of the subject's eye 12 and the output of the captured image may be processed via the image server 140.

[0084] Next, in step S112, image processing is performed to combine the image captured by the first ophthalmic apparatus 110 acquired in step S102 and the image captured by the second ophthalmic apparatus 120 acquired in step S110. In the next step S114, the image combined by the image processing is displayed in the display area 204 as the entire two-dimensional image 12G of the imaging range 12A.

[0085] The synthesis process of the captured image 203G by the first ophthalmic device 110 and the captured image 205G by the second ophthalmic device 120 may include, for example, a process of generating a stereoscopic image, a cross-sectional image, and a surface image of the retina using 3D data or scan data, and a process of executing a segmentation process. In addition, a fundus image may be generated using each of the data obtained from the SLO unit 18.

[0086] For example, when these images are to be synthesized, image processing such as rotating or enlarging / reducing the images may be performed so that the blood vessel patterns of the images overlap. The synthesized image can be a wide-angle image as if it were captured by an ophthalmic device for capturing wide-angle images with a field of view of 100 degrees or more. The image processing for synthesizing the images is not limited to the above-mentioned method, and it goes without saying that any known method may be used. The synthesized image is then stored and held in the image server 140.

[0087] FIG. 17 shows an example of an electronic medical record screen 220 in which a two-dimensional image 12G is displayed in the display area 204, the two-dimensional image 12G being a composite of an image 203G captured by the first ophthalmic apparatus 110 and an image 205G captured by the second ophthalmic apparatus 120.

[0088] As described above, in the fourth embodiment, an image of the center of the fundus and an image of the periphery of the central portion of the fundus are synthesized to obtain a two-dimensional image 12G of the entire imaging range 12A, thereby obtaining a wide-angle image as if it were captured by an ophthalmic device for capturing wide-angle images with a capturing angle of view of, for example, 100 degrees.

[0089] The imaging system 100 according to the fourth embodiment functions suitably when an ophthalmologist observes and diagnoses a fundus image 12G of the subject's eye 12. That is, a diagnosis is made based on a fundus image synthesized by the imaging system 100, and the diagnosis result is input using an electronic medical record function of an image viewer. When an AI diagnosis is to be performed on the fundus image 12G, a button 207 is pressed or clicked via an interface (not shown) to switch to an AI diagnosis mode. When an OCT image is required for diagnosis, a button 206 is pressed or clicked to switch to an OCT mode.

[0090] Ophthalmologists can accurately diagnose the central part of the fundus, such as the optic disc and macula, using a high-resolution central fundus image with a shooting angle of 30 degrees, and can also accurately determine whether or not there is a lesion in the peripheral retina using a synthesized fundus image 12G, which has a shooting angle of 100 degrees or more. On the other hand, ophthalmologists often own ophthalmic equipment for making diagnoses using high-resolution images of the fundus and retina. This high-resolution ophthalmic equipment has a photographing angle of view in the range of 10 to 30 degrees, and it is difficult to photograph the peripheral part of the fundus and retina beyond that range. Therefore, ophthalmologists need to purchase wide-angle and super-wide-angle fundus equipment separately for the peripheral part of the fundus and retina. In contrast, by using the image system 100 according to the fourth embodiment, it is possible to effectively utilize the high-resolution ophthalmic equipment owned and diagnose the central part of the fundus and retina using high-resolution images without purchasing new wide-angle and super-wide-angle fundus equipment. In addition, the peripheral part of the fundus and retina can be diagnosed using the synthesized fundus image with a wide angle of view of more than 100 degrees.

[0091] Fifth embodiment Next, a fifth embodiment will be described. The fifth embodiment is an ophthalmic apparatus including a plurality of optical systems. The same components as those in the above embodiments are denoted by the same reference numerals, and detailed description thereof will be omitted.

[0092] As shown in FIG. 18, the optical system 28A according to this embodiment includes a first optical system 28A1 and a second optical system 28A2. The optical system 28A further includes a switching mechanism 28B for switching the optical system used for imaging between the first optical system 28A1 and the second optical system 28A2 in response to an instruction from the control device 16. For example, a moving device such as a rotating stage or a one-axis stage may be used as the switching mechanism 28B. Below, an SLO image of the fundus F is illustrated, but is not limited thereto. As described above, the ophthalmic image handled by the ophthalmic device 10 may be an OCT image of the fundus F or an image of the anterior segment.

[0093] The optical system 28A1 is a narrow-angle optical system that provides an imaging range of about 45 degrees at an external irradiation angle A, for example. A narrow-angle fundus image depicting a fundus area near the optical axis AX is acquired using the optical system 28A1. The optical system 28A2 includes a reflection unit 280, and is a wide-angle optical system that provides an imaging range of about 130 degrees at an external irradiation angle A, for example, as described in the above embodiment. A wide-angle fundus image is acquired using the optical system 28A2. Here, as described in FIG. 6, the fundus image is not depicted in the center of the wide-angle fundus image, that is, in the vicinity of the optical axis AX. Therefore, in this embodiment, a wide-angle fundus image in which the fundus image is depicted in its entirety is generated using the narrow-angle fundus image acquired by the optical system 28A1 and the wide-angle fundus image acquired by the optical system 28A2. Note that the image synthesis of the narrow-angle fundus image and the wide-angle fundus image is as described above, and therefore a detailed description thereof will be omitted.

[0094] According to this embodiment, a narrow-angle fundus image and a wide-angle fundus image can be obtained using the narrow-angle optical system 28A1 and the wide-angle optical system 28A2. An ophthalmologist can accurately diagnose the central part of the fundus, such as the optic disc and the macula, using the narrow-angle fundus image, and can also diagnose the peripheral part of the retina using the combined wide-angle fundus image, if necessary.

[0095] Fig. 19 shows an example of a system using a removable optical module 28A-1. This optical module 28A-1 corresponds to the reflection unit 280, and specifically, it is effective to remove it together with the angle conversion lens L01 at the tip of the first lens group 281 shown in Figs. 7 and 9. As shown in FIG. 19, the switching mechanism 28B is responsible for the mechanism for attaching and detaching the optical module 28A-1. In this case, the switching mechanism 28B may move the optical module 28A-2 in the optical axis direction to fill the space between the subject's eye 12 and the optical module 28A-2 that occurs when the optical module 28A-1 is removed. In addition, the performance of the on-axis image can be improved by configuring the unit replaced with the optical module 28A-1 so that an additional lens is added to the tip of the optical module 28A-2 corresponding to the lens unit. In this way, a fundus imaging device that realizes both wide-field observation and narrow-field observation can be provided by the mechanism for attaching and detaching the optical module 28A-1.

[0096] Furthermore, in an optical system that enables super-wide-angle imaging of the peripheral area, stray light can be prevented by providing a light-shielding surface in the central area including the optical axis. Stray light can be reduced by limiting the irradiation area of ​​the scanning light from the SLO unit 18 and the OCT unit 20 to the annular area of ​​the imaging field of view.

[0097] Although the technology of the present disclosure has been illustrated using the embodiments, the technical scope of the technology of the present disclosure is not limited to the above embodiments. Various modifications or improvements can be made to the above embodiments without departing from the gist of the technology of the present disclosure. The forms to which such modifications or improvements are made are also included in the technical scope of the technology of the present disclosure. In addition, all documents, patent applications, and technical standards referred to in this specification are incorporated by reference in this specification to the same extent as if each document, patent application, and technical standard was specifically and individually stated to be incorporated by reference. [Explanation of symbols]

[0098] 10 Ophthalmology equipment 12 Examined eye 12A Imaging range 16 Control device 19 Scanning Device 28 Common optical system 28A Optical System 100 Imaging Systems 110 1st ophthalmological device 120 Second ophthalmological device 130 Network 140 Image Server 150 Computers A External coverage angle

Claims

1. An ophthalmic imaging optical system for an eye to be examined, comprising: a reflecting unit including a first concave mirror and a second concave mirror; and a lens unit that receives light from the reflecting unit, the first concave mirror and the second concave mirror have different focal lengths, and the focal length of the first concave mirror is longer than the focal length of the second concave mirror; the reflecting unit and the lens unit form a conjugate image of the pupil of the subject's eye, which is at a distance from the convex surface of the second concave mirror, on the opposite side of the reflecting unit to the subject's eye, the first concave mirror and the second concave mirror of the reflecting unit are arranged with their concave surfaces facing each other and each have an opening on the optical axis, the second concave mirror is formed with a second opening so as to pass light from the subject's eye to the first concave mirror, the first concave mirror is formed with a first opening smaller than the second opening of the second concave mirror, the first concave mirror reflects light from the subject's eye which is incident from the second opening of the second concave mirror to the second concave mirror, and the second concave mirror reflects the light reflected by the first concave mirror toward the lens unit through the first opening of the first concave mirror. Ophthalmic photography optical system.

2. Each of the first concave mirror and the second concave mirror is a parabolic mirror.

2. An ophthalmic photographing optical system according to claim 1.

3. The focal length of the first concave mirror is fa, the focal length of the second concave mirror is fb, When 0≦|fa−fb|≦0.1(fa+fb) The first concave mirror and the second concave mirror are formed so as to satisfy the conditional expression 3. An ophthalmic photographing optical system according to claim 1.

4. A light source that emits light of a predetermined wavelength; An ophthalmic photographing optical system according to any one of claims 1 to 3; a scanning member that scans the light from the light source toward the subject's eye via the lens unit and the reflection unit and is disposed at a position conjugate with a pupil of the lens unit; an imaging unit that images an image of the fundus of the subject's eye by the light scanned by the scanning member; 13. An ophthalmic device comprising:

Images